Softphone & Asterisk on same machine in centos?

I am using Asterisk & java application for voip project in centos.
java app use for keep Database with help of mysql & asterisk & monitor everything…
Now i am trying to use open source soft-phone on same machine where asterisk present.
I try pjsua but when ever asterisk on pjsua not work & when ever asterisk stop pjsua works…

Now i am also trying to find out in Asterisk there is App-Konference…is there way to fetch audio coming from 1 sip phone to asterisk & we can send it. like softphone do?

Means person who handle asterisk server he also talk with other sip phones… by headphone which attach to server’s sound card…

or by vbox i can keep running one more centos in same server where soft phone install & in main machine Asterisk, mysql,java etc running…& person can talk with same physical machine to sip phone…

Is this few possibilities i thing…but which one really possible not know?
Any Idea or clue can i get from here?

now as per david55 says

I want to ask…i have 1 pc which i am using as server of Asterisk & same containing mysql, java program & few sip phones i have…now when i establish all things as per various forums instructions…i can do different calls from sip phones via asterisk.
When i use 1 laptop which holds softphone, i can manage sip phone do calls softphone & vice versa…
Now i am trying Softphone & Asterisk etc on same pc. So can sip phone do call server’s softphone?
Following i understood after doing R and D.
Problem is if server ip then for all sip phone asterisk’s ip is same & asterisk redirect calls like calling then get request from & it redirect it to…now how asterisk redirect self ip…something like that i understood. Is it right?

Now mean time I read about oss.conf via google but not properly understood…!
Can i get some clue or help or idea?

Asterisk doesn’t normally redirect SIP. It normally has two different SIP connections for incoming and outgoing sides. The SIP connections will be to, not just You can make different user agents have different values for the 5060 part of this.

The ports for the audio are determined dynamically, so should not be a problem.